power: smb5-lib: exclusive typec mode operation

In USB Type-C mode, TRY_SINK/TRY_SRC and SRC_ONLY/SNK_ONLY are
mutually exlusive. To make force sink/src operation successful,
clear both TRY_SINK and TRY_SRC settings beforehand, and restore
the settings after switching back to DRP mode.

Change-Id: I7d2b7ea8ed41baef37ec2289ec7c43159cba9a55
Signed-off-by: Harry Yang <harryy@codeaurora.org>